Department of Psychology, University of Toronto, Toronto, Ontario M5S 3G3, Canada.
J Neurosci. 2010 Nov 3;30(44):14750-8. doi: 10.1523/JNEUROSCI.2687-10.2010.
We examined visual selective attention under perceptual load--simultaneous presentation of task-relevant and -irrelevant information--in healthy young and older adult human participants to determine whether age differences are observable at early stages of selection in the visual cortices. Participants viewed 50/50 superimposed face/place images and judged whether the faces were male or female, rendering places perceptible but task-irrelevant. Each stimulus was repeated, allowing us to index dynamic stimulus-driven competition from places. Consistent with intact early selection in young adults, we observed no adaptation to unattended places in parahippocampal place area (PPA) and significant adaptation to attended faces in fusiform face area (FFA). Older adults, however, exhibited both PPA adaptation to places and weak FFA adaptation to faces. We also probed participants' associative recognition for face-place pairs post-task. Older adults with better place recognition memory scores were found to exhibit both the largest magnitudes of PPA adaptation and the smallest magnitudes of FFA adaptation on the attention task. In a control study, we removed the competing perceptual information to decrease perceptual load. These data revealed that the initial age-related impairments in selective attention were not due to a general decline in visual cortical selectivity; both young and older adults exhibited robust FFA adaptation and neither group exhibited PPA adaptation to repeated faces. Accordingly, distracting information does not merely interfere with attended input in older adults, but is co-encoded along with the contents of attended input, to the extent that this information can subsequently be recovered from recognition memory.
我们在健康的年轻和老年成年参与者中检查了知觉负载下的视觉选择性注意——同时呈现与任务相关和不相关的信息——以确定在视觉皮层的选择早期是否可以观察到年龄差异。参与者观看了 50/50 叠加的人脸/地点图像，并判断这些人脸是男性还是女性，使地点可以感知但与任务无关。每个刺激都被重复，允许我们索引来自地点的动态刺激驱动竞争。与年轻成年人的完整早期选择一致，我们没有观察到在旁海马区位置区域 (PPA) 中对未注意到的地点的适应，并且在梭状回面孔区 (FFA) 中对注意到的面孔有明显的适应。然而，老年人既表现出 PPA 对地点的适应，也表现出 FFA 对面孔的弱适应。我们还在任务后探测了参与者对面孔-地点对的联想识别。发现具有更好地点识别记忆分数的老年参与者在注意任务中表现出最大的 PPA 适应和最小的 FFA 适应幅度。在一项对照研究中，我们去除了竞争的知觉信息以降低知觉负载。这些数据表明，选择性注意的初始年龄相关损伤不是由于视觉皮层选择性的普遍下降所致；年轻和老年成年人都表现出强大的 FFA 适应，并且两个组都没有对重复面孔的 PPA 适应。因此，在老年人中，分散注意力的信息不仅仅干扰注意力输入，而是与注意力输入的内容一起被共同编码，以至于可以从识别记忆中恢复这些信息。
